The effects of somatic cell count (SHS) and milk urea nitrogen (MUN) level on milk production and composition in some dairy cattle breeds

Abstract

In this study, the relationship between Somatic Cell Count (SCC) and Milk Urea Nitrogen (MUN) levels and their effects on milk composition were investigated some cows. In Red Danish, Simmental and Holstein cattles, average SCC’s were found to be 201.6±13.11x103 (Log10 SCC: 4.90±0622), 178.22±14.532 x103 (Log10 SCC: 4.90±0.567) and 305.7±94.37x103 cell ml-1 (Log10 SCC: 4.95±0.619), respectively. The average milk urea nitrogen (MUN) levels were measured as 8.07±0.221, 17.81±0.353, and 7.53±0.667 mg dl-1, respectively. Besides, 305 days milk yields were 7603.3±79.57, 8125.0±85.037 and 7995.9±216.51 kg; lactation lengths were 348.9±3.82, 380.0±14.26, 466.4±32.45 days; milk fat ratios were 3.60, 3.68 and 3.72%; milk protein ratios were 3.40, 3.55 and 3.33%; milk lactose ratios were 4.69, 4.73 and 4.67% and milk dry matter amounts were 12.41, 12.72 and 12.26% for Simmental, Red Danis and Holstein cattles, respectively. While the effect of urea classes on SCC was insignificant in the Simmental breed, it was significant (P<0.05) in the Red Danish and Holstein breeds. The effect of metabolic disease classes, however, was insignificant in the Simmental and Holstein breeds, and significant (P<0.05) in the Red Danish breed. The effect of SCC classes on MUN was found to be very significant (P<0.01) in Simmental and Red Danish breeds while it was determined as insignificant in Holstein breed andthe effect of metabolic disease classes was significant in all breeds (P<0.05). Additionally, differences between breeds were significant (P<0.05) in terms of metabolic disease such that ketosis rate was higher in Holstein breed compared to the other two breeds.

Keywords

• Dannish Red
• Holstein
• Simmental
• Somatic cell count
• Milk urea nitrogen

Bazı sütçü sığır ırklarında somatik hücre sayısı (SHS) ve süt üre nitrojen (MUN) seviyesinin süt verimi ve bileşimine etkileri

Öz

Bu araştırmada, somatik hücre sayısı (SHS) ve Süt üre nitrojeni (SÜN) seviyesinin birbirleri ile ilişkileri ve süt kompozisyonuna olan etkileri araştırılmıştır. Danimarka Kırmızısı, Simental, ve Siyah Alaca ırklarında SHS değerleri sırasıyla; 201.6±13.11x103 (Log10 SHS: 4.90±0.622), 178.22±14.532x103 (Log10 SHS: 4.90±0.567) ve 305.7±94.37x103 hücre ml-1 (Log10 SHS: 4.95±0.619); süt üre nitrojen (SÜN) değerleri sırasıyla; 8.07±0.221, 17.81±0.353 ve 7.53±0.667 mg dl-1; 305 günlük süt verimleri 7603.3±79.57, 8125.0±85.037 ve 7995.9±216.51 kg; laktasyon süresi 348.9±3.82, 380.0±14.26, , 466.4±32.45 gün; sütün yağ oranı %3.60, 3.68 ve 3.72; sütün protein oranı %3.40, 3.55 ve 3.33; sütün laktoz oranı %4.69, 4.73 ve 4.67; süt kuru madde oranı %12.41, 12.72 ve 12.26 olarak tesbit edilmiştir. SHS’na üre sınıflarının etkisi Sarı Alaca ırkında önemsiz, Danimarka Kırmızısı ve Siyah Alaca ırklarında ise önemli (P<0.05), metabolik hastalık sınıflarının etkisi Sarı Alaca ve Siyah Alaca ırkta önemsiz, Danimarka Kırmızısı ırkında ise önemli (P<0.05) bulunmuştur. SÜN değerine SHS sınıflarının etkisi Simental ve Danimarka Kırmızısı ırklarında çok önemli (P<0.01), Siyah Alaca ırkında ise önemsiz, metabolik hastalık sınıflarının etkisi tüm ırklarda önemli (P<0.05) bulunmuştur. Metabolik hastalıklar bakımından ırklar arasındaki farklar önemli (P<0.05) bulunmuştur. Siyah Alaca ırkında ketosis oranı diğer iki ırka göre daha yüksek, ketosis oranı ise daha düşük düzeyde bulunmuştur.

Anahtar Kelimeler

• Danimarka Kırmızısı
• Simental
• Siyah Alaca
• Somatik hücre sayısı
• Süt üre nitrojeni

Kaynakça

1. Abdouli, H., Rekik, B., & Haddad-Boubaker, A. (2008). Nonnutritional factors associated with milk urea concentrations under Mediterranean conditions. World Journal of Agricultural Science, 4 (2), 183-188.
2. Amaral-Philllips, D.M. (2005). Milk urea nitrogen-a nutritional evaluation tool. http://www.uky.edu/ Ag/AnimalSciences/dairy/exten sion/nut00029.pdf. (Erişim Tarihi: 15.12.2022).
3. Anonim (2011a). Hayvansal Gidalar İçin Özel Hijyen Kurallari Yönetmeliği. 27.12.2011 tarihli ve 28155 sayılı Resmî Gazete. https://www.resmigazete.gov.tr/eskiler/2011/12/ 20111227-10.htm. (Erişim Tarihi: 15.12.2022).
4. Anonim (2011b). Deneysel ve Diğer Bilimsel Amaçlar İçin Kullanilan Hayvanlarin Refah ve Korunmasina Dair Yönetmelik. https://www.resmigazete.gov.tr/eskiler/2011/12/20111213-4.htm. (Erişim tarihi: 15.12.2022).
5. Anonymous (2004). Commission Regulation (EC) No 853/2004 of the European Parliament and of the Council of 29 April 2004 laying down specific hygiene rules for food of animal origin. Official Journal of the European Union, 139, 30-205. https://www. fsai.ie/uploadedFiles/Reg853_2004(1).pdf
6. Anonymous (2022). Somatic Cell Count, an indicator of milk quality. https://ahdb. org.uk/somatic-cell-count-milk-quality-indicator. (Erişim tarihi: 15.12.2022).
7. Atalay, H. (2019). Milk fat/protein ratio in ketosis and acidosis. Balıkesir Sağlık Bilimleri Dergisi, 8(3), 143-146.
8. Ayasan, T. (2009). Süt ineklerinin beslenmesinde süt üre nitrojenin önemi. Gaziosmanpaşa Üniversitesi Ziraat Fakültesi Dergisi, 26 (2), 27-33. https://dergipark.org.tr/en/pub/gopzfd/issue/7335/95981.

9. Ayașan, T., Hızlı, H., Yazgan, E., Kara, U., & Gök, K. (2011). The effect of somatic cell count on milk urea nitrogen and milk composition. Kafkas Üniversitesi Veteriner Fakültesi Dergisi, 17 (4), 659-662. https://doi.org/10.9775/kvfd.2011.4489
10. Barlowska, J., Litwinczuk, Z., Wolanciuk, A., & Brodziak, A. (2009). Relationship of somatic cell count to daily yield and technological usefulness of milk from different breeds of cows. Polish Journal of Veterinary Sciences, 12 (1), 75-79.
11. Berge, A.C., & Vertenten, G.A. (2014). A field study to determine the prevalence, dairy herd management systems, and fresh cow clinical conditions associated with ketosis in European dairy herds. Journal of Dairy Science, 97 (4), 2145-2154. https://doi.org/10.3168/jds.2013-7163.
12. Berglund, B., & Larsson, K. (1983). Milk ketone-bodies and reproduction performance in postpartum dairy cows. Proceedings of the 5th International Conference on Production Disease in Farm Animal, Uppsala. Sweden. 153-157p.
13. Blanchard, T., Ferguson, J., Love, L., Takeda, T., Henderson, B., Hasler, J., & Chalupa, W. (1990). Effect of dietary crude-protein type on fertilization and embryo quality in dairy cattle. American Journal of Veterinary Research, 51 (6), 905-908.
14. Burgos, S.A., Fadel, J.G., & de Peters, E.J. (2007). Prediction of ammonia emission from dairy cattle manure based on milk urea nitrogen: Relation of milk urea nitrogen to ammonia emissions. Journal of Dairy Science, 93 (6), 2377-2386. https://doi.org/10.3168/jds.2009-2415
15. Çardak, A.D. (2016). Siyah-Alaca İneklerde somatik hücre sayısı, laktasyon sırası ve döneminin süt verimi ve süt bileşimine etkileri. Harran Üniversitesi Veteriner Fakültesi Dergisi , 5 (1), 34-39. https:// dergipark.org.tr/en/pub/ huvfd/issue/29582/317345
16. Çınar, M., Serbester, U., Ceyhan, A., & Gorgulu, M. (2015). Effect of somatic cell count on milk yield and composition of first and second lactation dairy cows. Italian Journal of Animal Science, 14 (1), 3646. https://doi.org/10.4081/ijas.2015.3646
17. Dejyong, T., Chanachai, K., Immak, N., Prarakamawongsa, T., Rukkwamsuk, T., Tago Pacheco, D., & Phimpraphai, W. (2022). An economic analysis of high milk somatic cell counts in dairy cattle in Chiang Mai, Thailand. Front Veterinary Science, 9, 958163. https://doi.org/10.3389/fvets.2022.958163
18. Depatie, C. (2000). Nutritional, managerial, physiological, and environmental factors affecting milk urea nitrogen in Quebec Holstein cows: A field trial. Master of Sci., digitool.library. mcgill.ca:8881/ dtl_publish/8/30815.html
19. DePeters, E.J., & Cant, J.P. (1992). Nutritional factors influencing the nitrogen composition ofbovine milk: a review. Journal of Dairy Science, 75 (8), 2043-2070. https://doi.org/10.3168/jds.S0022-0302(92) 77964-8
20. Diab, I.A.K., & Hillers, J.K. (1996). Effect of selection for milk yield and dietary energy on yield traits; bovine somatotropin and plasma urea nitrogen in dairy cows. Journal of Dairy Science, 79 (4), 682-688. https://doi.org/10.3168/jds.S0022-0302(96)76414-7
21. Duffield, T.F., Kelton, D.F., Leslie, K.E., Lissemore, K.D., & Lumsden, J.H. (1997). Use of test day milk fat and milk protein to detect subclinical ketosis in dairy cattle in Ontario. Canadian Veterinary Journal, 38 (11), 713-18.
22. Ferguson, J.D., & Chalupa, W. (1989). Impact of protein nutrition on reproduction in dairy cows. Journal of Dairy Science, 72 (3), 746-766. https://doi.org/10.3168/jds.S0022-0302(89)79168-2
23. Ferguson, J.D., Blanchard, T., Galligan, D.T., Hoshall, D.C., & Chalupa, W. (1988). Infertility in dairy cattle fed a high percentage of protein degradable in the rumen. Journal of the American Veterinary Medical Association, 192 (5), 659-662. PMID: 3372318
24. Filipejová, T., Kováčik, J., Kirchnerová, K., & Foltys, V. (2009). Changes in milk composition as a result of metabolic disorders of dairy cows. Potravinárstvo, 5 (1), 10-16.
25. Geishauser, T., Leslie, K., Tenhag, J., & Bashiri, A. (2000). Evaluation of eight cow-side ketone tests in milk for detection of subclinical ketosis in dairy cows. Journal of Dairy Sciene, 83 (2), 296-299. https://doi.org/10.3168/jds.S0022-0302(00)74877-6
26. Genç, S., & Soysal, M. (2018). Türkiye siyah alaca sığır populasyonlarında süt ve döl verimi. Tekirdağ Ziraat Fakültesi Dergisi, 15 (1), 76-85. https://dergipark.org.tr/en/pub/jotaf/issue/ 35312/ 305033
27. Godden, S.M., Kelton, D.F., Lissemore, K.D., Walton, J.S., Leslie, K.E., & Lumsden, J.H. (2001a). Milk urea testing as a tool to monitor reproductive performance in Ontario dairy herds. Journal of Dairy Science, 84 (6), 1397-1406. https://doi.org/10.3168/jds.S0022-0302(01)70171-3
28. Godden, S.M., Lissemore, K.D., Kelton, D.F., Leslie, K.E., Walton, J.S., & Lumsden, J.H. (2001b). Relationships between milk urea concentrations and nutritional management, production, and economic variables in Ontario dairy herds. Journal of Dairy Science, 84 (5), 1128-1139. https://doi.org/ 10.3168/jds.S0022-0302(01)74573-0
29. Gökçe, G., Kayaalp, G.T., & Güney, M.Ç. (2020). The effect of season, lactation number and type score on somatic cell count in black and white cattle. Turkish Journal of Agriculture-Food Science and Technology, 8 (9), 2017-2020. https://doi.org/10.24925/turjaf.v8i9.2017-2020.3728
30. Guo, K., Russek-Cohen, E., Varner, M.A., & Kohn, R.A. (2004). Effects of milk urea nitrogen and other factors on probability of conception of dairy cows. Journal of Dairy Science, 87 (6), 1878-1885. https://doi.org/10.3168/jds.S0022-0302(04)73346-9
31. Hojman, D., Gips, M., & Ezra, E. (2005). Association between live body weight and milk urea concentration in Holstein cows. Journal of Dairy Science, 88 (2), 580-584. https://doi.org/ 10.3168/jds.S0022-0302 (05)72721-1
32. Hojman, D., Kroll, O., Adin, G., Gips, M., Hanochi, B., & Ezra, E. (2004). Relationship between milk urea and production, nutritional fertility traits in Israeli dairy herds. Journal of Dairy Science, 87 (4), 1001-1011. https://doi.org/10.3168/jds.S0022-0302(04)73245-2
33. Hollmann, M., Allen, M.S., & Beede, D.K. (2011). Dietary protein quality and quantity affect lactational responses to corn distillers grains: A metaanalysis. Journal of Dairy Science, 94 (4), 2022-2030. https://doi.org/10.3168/jds.2010-3712
34. Hutjens, M., & Chase, L.E. (2019). Interpreting Milk Urea Nitrogen (MUN) Values. https://dairy-cattle.extension.org/interpreting-milk-urea-nitrogen-mun-values/. (Erişim tarihi: 15.12.2022).
35. Hutu, I., & Onan, G.W. (2019). Animal production: Practical exercises for veterinary medicine. [Chapter 5. Milk Production Records: 5.11. Mılk Urea Nıtrogen (MUN)]. 2nd ed.. - Timişoara : Agroprint, 2019. Conţine bibliografie. ISBN: 978-606-785-102-1. http://dx.doi.org/10.13140/RG.2.2.27939.20004
36. Ishler, V.A. (2008). Interpretation of milk urea nitrogen values. PennState Extension, DAS, 2008, 134. https://extension.psu.edu/interpretation-of-milk-urea-nitrogen-mun-values
37. Jarshaji, O., & Zülkadir, U. (2019). Konya ilinde özel bir işletmede yetiştirilen siyah alaca sığırların bazı süt verim özelliklerine ait fenotipik parametre tahminleri. KSÜ Tarım ve Doğa Dergisi, 22 (Ek Sayı:1), 162-168. https://doi.org/10.18016/ksutarimdoga.v22i49073.561738
38. Johnson, R.G., & Young, A.J. (2003). The association between milk urea nitrogen and DHI production variables in Western commercial dairy herds. Journal of Dairy Science, 86 (9), 3008-3015. https://doi.org/10.3168/jds.S0022-0302(03)73899-5
39. Jonker, J.S., Kohn, R.A., & Erdman, R.A. (1999). Milk urea nitrogen target concentrations for lactating dairy cows fed according to National Research Council recommendations. Journal of Dairy Science, 82 (6), 1261-1273. https://doi.org/10.3168/jds.S0022-0302(99)75349-X
40. Kara, Ç. (2013). Physiological and metabolic changes during the transition period and the use of calcium propionate for prevention or treatment of hypocalcemia and ketosis in periparturient cows. Journal of Biodiversity and Environmental Sciences, 7 (19), 9-17.
41. Karaağaç, M., & Genç, S. (2019). Kırşehir ilinde yetiştirilen siyah alaca sığırlarının süt verim özelliklerinin belirlenmesi. Tekirdağ Ziraat Fakültesi Dergisi, 16 (3), 412-422. https://doi.org/10.33462/jotaf.590659
42. Karslıoğlu-Kara, N., & Koyuncu, M. (2018). A research on longevity, culling reasons and milk yield traits in between Holstein and Simmental cows. Mediterranean Agricultural Sciences, 31 (3), 325-329. https://doi.org/10.29136/mediterranean.443409
43. Karslıoğlu-Kara, N., Galiç, A., & Çevik, S. (2021). Simental ırkı ıneklerde bazı verim özellikleri ve sağlık sorunları arasındaki ılişkinin belirlenmesi. Akademik Ziraat Dergisi, 10 (2), 411-418. https://doi.org/10.29278/azd.881922
44. Kaygısız, A. (2023). Esmer sığırlarda somatik hücre sayısı ve süt üre nitrojen miktarının sütün bileşimine etkileri. Palandöken Journal of Animal Science, Technology and Economics, 2 (1), 1-6. https://dergipark.org.tr/tr/pub/paste/issue/71334/1158853
45. Kaygısız, A., & Karnak, İ. (2012). Kahramanmaraş’ta süt sığırı işlemelerinden toplanan çiğ süt örneklerinin somatik hücre sayısının AB normları ve subklinik mastitis bakımından değerlendirilmesi. KSÜ Doğa Bilimleri Dergisi, 15 (3), 9-15. https://dergipark.org.tr/en/pub/ ksudobil/issue/22834/243772
46. Kaygusuz, E., & Akdağ, F. (2021). Effect of cold stress on milk yield, milk composition and some behavioral patterns of simmental cows kept in open shed barns. Kocatepe Veterinary Journal, 14 (3), 351-358. https://doi.org/10.30607/kvj.952295
47. Kelly, A.L., Tiernan, D., O'sullivan, C., & Joyce, P. (2000). Correlation between bovine milk somatic cell count and polymorphonuclear leukocyte level for samples of bulk milk and milk from individual cows. Journal of Dairy Science, 83 (2), 300-304. https://doi.org/10.3168/jds.S0022-0302(00)74878-8
48. Koç, A. (2007). Daily milk yield, non-fat dry matter content and somatic cell count of Holstein-Friesian and Brown-Swiss cows. Acta Veterinaria, 57 (5-6), 523-535. https://doi.org/10.2298/AVB0706523K
49. Koç, A. (2015). Effects of somatic cell count and various environmental factors on milk yield and foremilk constituents of Red-Holstein cows. Journal of Agricultural Sciences, 21 (3), 439-447. https://doi.org/ 10.15832/ankutbd.25135
50. Koç, A., & Arı, Ç. (2020). Milk Yield, Reproduction and Milk Quality Characteristics of Simmental and Red-Holstein Cattle Raised At A Dairy Farm In Aydın Province: 2. Milk Quality. Turkish Journal of Agriculture-Food Science and Technology, 8 (10), 2074-2080. https://doi.org/10.24925/turjaf. v8i10.2074-2080.3512
51. Koç, A., & Gürses, R. (2020). A Study on Milk Yield, Fertility and Milk Quality Characteristics of Primiparous Red-Holstein and Holstein-Friesian Cows. Turkish Journal of Agriculture-Food Science and Technology, 8 (12), 2562-2569. https://doi.org/10.24925/turjaf.v8i12.2562-2569.3690
52. Koç, A., & Kızılkaya, K. (2009). Some factors influencing milk somatic cell count of Holstein Friesian and Brown Swiss cows under the Mediterranean climatic conditions. Archives Animal Breeding, 52 (2), 124-133. https://doi.org/10.5194/aab-52-124-2009
53. Koçbeker, V., & Bahtiyarca Y. (2016). Konya bölgesinde süt sığır yetiştiriciliği yapan çiftliklerin besleme programlarının değerlendirilmesi konusunda bir çalışma. International Symposium:Bozkır From Past to Present, 06-08 Mayıs 2016, Konya.
54. Korhonen, H., & Kaartinen, L., (1995). Changes in the composition of milk induced by mastitis. In: M. Sandholm, T. Honkanen-Buzalski, L. Kaartinen, S. Pyörälä (eds.) The bovine udder and mastitis. Gummeruskirjapaino Oy, Jyväskylä, Finland, pp. 76-82.
55. Litwinczuk, Z., Krol, J., Brodziak, A., & Barlowska, J. (2011). Changes of protein content and its fractions in bovine milk from different breeds subject to somatic cell count. Journal of Dairy Sciences, 94 (2), 684-691. https://doi.org/10.3168/jds.2010-3217
56. Ma, Y., Ryan, C., Barbano, D.M., Galton, D.M., Rudan, M.A., & Boor, K.J. (2000). Effects of somatic cell count on quality and shelf-life of pasteurized fluid milk. Journal of Dairy Science, 83 (2), 264-274. https://doi.org/10.3168/jds.S0022-0302(00)74873-9
57. Mıtev, J., Gergovska, Z., Mıteva, T., Vasılev, N., Uzunova, K., & Penev, T. (2013). Effect of the degree of udder contamination in dairy cows on the somatic cell count in milk. İ.Ü. Veteriner Fakültesi Dergisi, 39 (1), 76-83. https://dergipark.org.tr/en/pub/iuvfd/issue/18531/195621
58. Min, D.H. (2022). What is Milk Urea Nitrogen and How is It Interpreted?. Food Mr C Biology-Extension Forage Specialist, MSU UPES. 2013. https://www.canr.msu.edu/uploads/files/Research_Center/ UPREC/Animal_Nutrition/milk_urea_nitrogen.pdf
59. Ng-Kwai-Hang, K.F., Hayes, J.F., Moxley, J.E., & Monardes, H.G. (1985). Percentages of protein and nonprotein nitrogen with varying fat and somatic cells in bovine milk. Journal of Dairy Science, 68 (5), 1257-1262. https://doi.org/10.3168/jds.S0022-0302(85)80954-1
60. Nielen, M., Aarts, M.G., Jonkers, A.G., Wensing, T., & Schukken, Y.H. (1994). Evaluation of two cow side tests for the detection of subclinical ketosis in dairy cows. Canadian Veterinary Journal, 35 (4), 229-232.
61. Nourozi, M., Moussavi, A.H., Abazari, M., & Zadeh, M.R. (2010). Milk urea nitrogen and fertility in dairy farms. Animal and Veterinary Advances, 9 (10), 1519-1525. http://docsdrive.com/.../1519-1525.pdf
62. Olechnowicz, J., & Jaśkowski, J.M. (2012). Somatic cells count in cow's bulk tank milk. Journal of Veterinary Medical Science, 74 (6), 681-686. https://doi.org/10.1292/jvms.11-0506
63. Orhan, H., Efe, E., & Şahin, M. (2004). SAS yazılımı ile istatistiksel analizler. Tuğra Ofset, Isparta, 139.
64. Önal, A.R., Özkan, M., & Tuna, Y.T. (2021). Siyah Alaca süt sığırlarında mevsim ve laktasyon sırasının sütün bileşimi ve kalitesine etkisi. Tekirdağ Ziraat Fakültesi Dergisi, 18 (2), 368-374. https://doi.org/10.33462/jotaf.831567
65. Özkan, M. (2017). Süt sığırlarında somatik hücre sayısının süt bileşimi ve kalitesine etkisi (Tez No: 457201). [Yüksek Lisans Tezi, Namık Kemal Üniversitesi Fen Bilimleri Enstitüsü Zootekni Ana Bilim Dalı]. Yükseköğretim Kurulu Ulusal Tez Merkezi.
66. Rajala-Schultz, P.J., & Saville, W.J.A. (2003). Sources of variation in milk urea nitrogen in Ohio dairy herds. Journal of Dairy Science, 86 (5), 1653-1661. https://doi.org/10.3168/jds.S0022-0302(03) 73751-5
67. Richardt, W. (2004). Milchinhaltsstoffe als Indikatoren für die Fütterung und Gesundheit von Milchkühen. http://www.vilomix.de/pdf_files/tiererhnaehrung/ 2004_ milchinhaltsstoffe_ fuetterung_ richardt_ vilo mix_04.pdf (18.04.2016.
68. Roy, B., Brahma, B., Ghosh, S., Pankaj, P.K., & Mandal, G. (2011). Evaluation of milk urea concentration as useful indicator for dairy herd management: A review. Asian Journal of Animal Veterinary Advanced, 6 (1), 1-19. https://10.3923/ajava.2011.1.19
69. Sarar, A., & Tapkı, İ. (2017). Türkiye’de yetiştirilen Holştayn İneklerde süt verim özelliklerine ait fenotipik ve genotipik parametre tahminleri. Türk Tarım - Gıda Bilim ve Teknoloji Dergisi, 5 (10), 1243-1249. https://doi.org/10.24925/turjaf.v5i10.1243-1249.1434
70. SAS (1985). SAS User’s Guide: Statistics, SAS institute Inc., Carry, NC, USA.
71. Sharma, N., Singh, N., & Bhadwal, M. (2011). Relationship of somatic cell count and mastitis: An overview. Animal Bioscience, 24 (3), 429-438. https://doi.org/10.5713/ajas. 2011. 10233
72. Şahin, O., Kaygısız, A., & Yılmaz, İ. (2022). Türkiye’de Sığır Yetiştiricilerinin Irk Tercihleri ve Nedenleri. Uluslararası Tarım ve Yaban Hayatı Bilimleri Dergisi, 8 (1), 151-165. https://doi.org/10.24180/ijaws.1052823
73. Wenninger, A., & Distl, O. (1994). Urea and acetone in milk as indicators for nutrition dependent reproductive disorders in dairy cows. Dentsche Tierarztliche Wochenschrift, 101, 152-157.
74. Yalçın, H., & Çakmak, T. (2022). İnek sütlerinde somatik hücre sayısı ve bazı parametrelerin araştırılması. Manas Journal of Agriculture Veterinary and Life Sciences, 12 (1), 81-87. https://doi.org/10.53518/ mjavl. 1092994
75. Yoon, J.T., Lee, J.H., Kim, C.K., Chung, Y.C., & Kim, C.H. (2004). Effects of milk production, season, parity and lactation period on variations of milk urea nitrogen concentration and milk components of Holstein dairy cows. Asian-Australasian Journal of Animal Sciences. Asian Australasian Association of Animal Production Societies, 17 (4), 479-484. https://doi.org/10.5713/ajas.2004.479